Gunkballs : Symptom of adrifting program

Gunkballs, sticky deposits, hard-to-remove fouling

This phenomenon has been observed since the early use of film-forming amines (FFAs) in industrial systems in the 1970s, often referred to as first-generation FFAs. It results from the accumulation of fatty amines combined with iron oxides, forming deposits that can range from minor aesthetic issues to severe operational constraints, including clogged steam traps, blocked valves, and fouled strainers.

In practice, gunkball formation is not random. It is typically driven by a combination of overly rapid surface cleaning and localized accumulation of active substances. These conditions promote agglomeration and reflect a deeper issue: a lack of control over formulation and/or application of the treatment program.

Beyond the CAS Number: Understanding True Quality
Identical CAS numbers do not guarantee identical performance. While chemical registry numbers ensure identification, they do not reflect formulation balance, volatility behavior, or distribution within steam and condensate phases. In FFAs programs, performance is governed by physico-chemical behavior and system-specific implementation—not by the molecule alone.

So how do you respond when gunkballs are already present in your system?
The answer is not to increase dosage or apply aggressive cleaning. The priority is to regain control of system behavior.

Step 1 – Understand why the system drift

An FFAs program must be approached as a physico-chemical equilibrium system, not as a simple product application. Its performance is governed by a combination of parameters including Henry’s law constant, temperature and pressure conditions, blend composition, and the vapor-liquid distribution coefficient.

Step 2 – Design the right remediation strategy

Once the root cause is understood, remediation must follow a controlled and structured approach. The objective is twofold: first, to stop ongoing deposit formation by restoring proper balance in the treatment program; second, to progressively remove existing deposits without disrupting system stability.

This requires a gradual online cleaning strategy, where deposits are slowly re-solubilized rather than aggressively removed. Sudden cleaning actions often destabilize the system, leading to redeposition or operational issues. Controlled re-solubilization ensures that deposits are eliminated while maintaining process continuity and equipment protection.

Over the years, specific formulations have been developed and validated to address these situations effectively, combining controlled cleaning action with stabilization of the FFAs program.

Case Study – Introduction

System in place

• 4 steam boiler units: 200,000 lb/h each
• Operating pressure: 600 psi
• Estimated condensate return: 50%

Water and Chemical Treatment

• DI make-up water: < 1 µS/cm
• Feedwater conductivity: 5 to 15 µS/cm
• Boiler setpoint: < 250 µS/cm
• Initial chemical treatment: sodium hydroxide, trisodium phosphate, and sulfites

The boiler water treatment program was transitioned by a competitor to a 2nd generation FFAs based program (along with sodium hydroxide) to improve system protection under increasingly cyclic operating conditions.

First Results
No corrosion observed, however:

• Progressive deposits and build-up observed from the deaerator tank through to the boilers
• Difficulties maintaining stable pH in the condensate system

Case Study – Tackling the problem

Deposit analysis revealed significant iron and silica content, with organic matter representing 60 to 95% of the composition, which is consistent with typical FFAs-related deposits. Infrared analysis confirmed the presence of amine functional groups, along with aliphatic radicals commonly associated with fatty amines.

Following a full audit of the installation and detailed deposit characterization, the remediation strategy focused on restoring system balance:

• Stop NaOH injection to stabilize the chemistry (increase in cycles of concentration, reduced chemical risk, lower salt precipitation potential, and mitigation of caustic corrosion at the waterline)
• Implement a controlled online cleaning program using a 5th-generation FFA-based formulation, designed to gradually re-solubilize deposits while maintaining system stability

Image 1: Initial state – start of the program, deposits already present within the system

Image 2: Year 1 – build-ups still visible, reflecting ongoing re-solubilization and system adjustment

Image 3: Year 2 – clear reduction in deposits, stabilization of treatment behavior

Image 4: Year 3 – continued improvement, with significant recovery of system cleanliness and control

Effective remediation is not immediate. Controlled online cleaning requires time to re-solubilize deposits without destabilizing the system, ensuring long-term performance rather than short-term disruption.

Conclusion – Mastering FFAs Programs

Gunkballs and build-up are the visible consequence of a loss of control over FFAs program behavior.

Even in well-managed, high-purity systems, a treatment program can drift if the underlying physico-chemical balance is not fully controlled. The absence of corrosion is not a guarantee of performance. Stability, distribution, and predictability are the true indicators.

Effective remediation requires a structured approach: understanding system behavior, restoring equilibrium, and implementing controlled, long-term cleaning strategies. When properly executed, this approach not only removes existing deposits but also prevents their recurrence.

Ultimately, the performance of an FFAs program is not defined by the product itself or by CAS numbers in an SDS, but by the ability to control its behavior within the system.

Key message

Same chemistry does not mean same performance. Control does.

Do you fully understand how your program behaves inside your system?